Drilling apparatus



Aug. 30, 1938. J. 1.. REILLY DRILLING APPARATUS Filed Dec. 26, 1935 Ina/ 72307: J57z7zZ.ZE62iZZy. Zy-

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Patented Aug. 30, 1938 UNITED STATES PATENT OFFICE 2,128,321 DRILLING APPARATUS Massachusetts Application December 26, 1935, Serial No. 56,166

8 Claims.

My invention relates to drilling apparatus, and more particularly to drilling apparatus of the percussive, automatic rotation type.

In the operation of rock drilling and the like by percussive motors, it is common in a considerable majority of instances to use a hammer drill, so-called, in which the reciprocation of the hammer element automatically effects the rotation of the drilling implement in such a manner that the cutting edges of the latter are moved appropriately between successive blows so that maximum efiiciency in drilling is secured.

In most such devices, it is now common to employ a rifle bar turning with the hammer piston on one motion of the latter, and automatically held against turning in the opposite direction during the reverse pass of the hammer piston. Such apparatus is highly effective and, as above noted, is most widely used. There are times, however, such as during spotting, during the pulling of stuck steels, during the driving of a steel of slightly larger gauge than the diameter at the bottom of the hole, to the bottom of the hole for the purpose of there continuing drilling, and with drills which are used both for the formation of round holes and, with appropriate guides for their implements for broaching out material between adjacent holes, during the broaching operation, when it is desirable to be able to discontinue the rotation temporarily and to cause reciprocation of the hammer piston without rotation thereof. Devices for this purpose have been provided, but apparently none of a completely satisfactory nature has been produced; 35. and it is an object of my invention to provide an improved rotation release mechanism for a percussive motor, which will most effectively and successfully meet the needs of practice. It is another object of my invention to provide an improved drilling motor having improved means for selectively causing intermittent rotation of its piston or, at will, reciprocation of the piston unattended by rotation. It is a further object of my invention to provide an improved rotation release mechanism for a drill of the type in which the piston is intermittently rotated through the use of a rifle bar and ratchet and pawl means.

It is still a further object of my invention to provide an improved means for rendering a ratchet and pawl mechanism ineffective at will.

Other objects and advantages of my invention will hereinafter appear.

In the accompanying drawing, in which, for purposes of illustration, a preferred form and certain modifications of my invention have been shown- Fig. 1 is a central longitudinal section through a drilling motor in which the preferred form of my invention is incorporated.

Figure 2 is a transverse section on the of the line 2--2 of Fig. 1.

Fig. 3 is a transverse section on the plane of the line 3 -3 of Fig. 1.

Fig. 4 is a fragmentary section on the plane plane of the line 46 of 1. v i

Fig. 5 is a perspective View of an element of the improved rotation release mechanism as illustrated in the first embodiment oi." the invention shown.

Fig. 6 is a perspective view of a corresponding element of different construction.

Fig. '7 is a view similar to Fig. 2, showing a modified form of construction for use with drills having a very high rate of rotation.-'

Fig. 8 is a fragmentary sectional detail view showing a further modification. v

Referring to the drawing, it will be observed that a drilling motor I is provided with a cylinder member 2 having a bore 3 in which a hammer piston 4, provided with a striking bar 5, is reciprocable. The cylinder has a front head 6 and a built-up rear head 1 comprising a plurality of elements, among which are elements 8 and 9, locked against rotation relative to each other and the drill by a dowel Ill, and. forming between them a chamber II in which a distributing valve I2 is reciprocably disposed, said distributing valve controlling the distribution of fluid, supplied from a chamber 13 under the control of a throttle valve l4, appropriately to the opposite ends of the cylinder bore 3, to move the piston 4 oppositely. Because the valve I2 may assume a wide variety of forms, and because in the form illustrated it is a well known article of commerce, a detailed description of the distributing valve and the distribution passages is unnecessary, it being simply desired to point out that appropriate means is provided for the purpose of eifecting rapid opposite reciprocatory move:- ments of the piston 4 under the action of an expansible fluid.

The striking bar 5 is provided with splineways l5 interengaging with splines IS on a chuck nut 11 which is appropriately held within a rotatable chuck driving member I8 with which a steel rotating and retaining member 19 is appropriately interlocked, as at 20; the parts l1, l8, I9 and 9 being enclosed in a suitablechuck housing 2| secured to the forward end of the cylinder memher 2 in any well known manner.

Turning now to the rotation-effecting mechanism, it will be noted that to the rear of the member 9, and within a bore 23 in which the members 8 and 9 are slidably received, there are arranged additional elements between the rear of the element 9 and the forward end of a rear head member proper 24. These elements include a ratchet ring 26, a closure ring 21, and a floating ring 28; and a rifle bar 29 having a pawl carrying portion 30 is rotatably supported in bores 31 in the member 9 and 32 in the member 21. It will be observed that the floating ring 28 is received in an annular groove 33 formed in the rear end of the ratchet ring 26, and that it surrounds a reduced portion of the pawl carrying part 38 associated with the rifle bar 29. The pawl carrying member 30 is provided with a number of recesses 35 receiving pawls 36, which are pressed outwardly by followers 31, upon which springs 38 act. The ratchet ring 26 is provided with a series of internal teeth 39 selectively engageable by the various pawls 36; and commonly, by appropriate formation of the pawls and location thereof, but one pawl is in full engagement with a ratchet tooth 39, other pawls progressively having diminishing extents of engagement with the teeth so that the degree of angular advance between pawl engagement is reduced and backlash virtually eliminated.

The floating ring 28 is not truly annular, in the sense of having truly circular inner and outer concentric peripheries, in the illustrative embodiments of my invention herein shown. However, in each form illustrated it possesses an outer peripheral surface 48 coaxial with the rifle bar axis, and it is adapted tobe held, at will, by any suitable means, against rotation, as for example, by a manually rotatable screw-threaded member 42 having a spring 43 for maintaining it in its different adjusted positions, and projectable into engagement with the rearwardly facing surface of the element 28, as indicated in Fig. l.

The form of the floating member 28 may bviously differ radically. It may be internally of modified rectangular form, as shown in Fig. 5, having lobes 44 to provide arcuate surfaces struck from the ring axis, as later described; it may be relatively rectangular internally, as shown at 45 on ring 28' in Fig. 6; and, where but a pair of pawls 36 is used, as in Fig. 7, and a pair of pawl plungers 31, the floating member 28" may be more nearly oval in form; and it will be evident that other forms may be employed if desired, for example, such a one as is shown in Fig. 8, in which it will be noted that the pawl-carrying part of the rifle bar is not cut away as in the earlier forms mentioned, but instead the ring 28 has a bore 55 which is truly circular except for small lobe-like recesses 58 opposite the ends of the pawls, and the diameter of the bore 55 is but slightly smaller than the inside circle of the toothed ratchet ring. In all forms shown it will be noted that the inner wall of the floating ring comprises portions which permit free engagement of the pawls with the ratchet teeth, and portions which, when engaged by the tips of the pawls, depress the latter into positions in which contact with the ratchet teeth is precluded.

It will be appreciated that the form of the member 28 will be determined in a measure by the rate of rotation which the drill is designed to accomplish, one form being suitable where the rate of rotation is relatively slow, a modified form being needed where the rate of rotation is more rapid, and a further modified form being necessary in the case of extremely rapid rotation. Of course it will be appreciated that the rate of rotation is a function of the lead of the thread 4''! on the rifle bar 29 and of the cooperating thread 48 on the rifle nut 49; the form of construction shown in Fig. 6 being adapted for a slower rate of rotation than the form of Fig. 5, and both'adapted for slower rates of rotation than the form of construction shown in Fig. 7. The form of Fig. 8 would function similarly to that of Fig. 5.

The mode of operation may now be described, but it will be well first again to note that each of the floating rings 28,28, 28 and 28" has within it pawl engaging surfaces which are, at certain points therein, separated from each other, along lines passing through the axis of rotation of said rings, by distances less than the diameter of the cylindrical surface which would include the innermost points on the ratchet teeth 38. For example, in Fig. 5, in which the inner wall of the ring 28 is formed with four identical surfaces the distances between the axis 0 of the ring and the points A, B and C in a surface 51 along the lines OA, OB, and 0C, are all less than the distance OD in Fig. 2; while the distances OE, OF and 0G are progressively greater, so that with the point G opposite the end of a pawl, the pawl may fully engage within the space between a pair of adjoining ratchet teeth. Similarly, the distance OI-I in Fig. 6, between the central point in one of the four similar sides 52 of the ring 28 and the axis 0' of ring 28, is less than the radius of the inside circle of the ratchet ring; while the distance OI is greater than the radius of the root circle of the ratchet ring. In like manner, the radial distance between the generally arcuate surfaces 53 of the ring member 28" in Fig. '7 and the axis of the ring is substantially less than the radial distances from the axis of the pawl carrier to the inner points of the ratchet teeth. Correspondingly, the lobe-like recesses 58 in Fig. 8. permit ratchet and pawl engagement, but the main wall areas 55 of the bore are adapted to preclude pawl contact with the ratchet teeth.

It should next again be noted that the pawls are of such length that, while at one end, and throughout the major portion of their respective widths, they lie within and are adapted to contact with the ratchet teeth, their rearmost portions extend within the openings in the floating ring members 28, 28, 28", and 28"; and accord-- ingly, when the outer ends of the pawls are engaged by those surfaces of the ring members 28, 28, 28" and 28" which have been described as nearer the axis of the ring than the innermost points of the ratchet teeth are near to the line in which the axis of the ring lies, the pawls will be held out of engagement with the ratchet teeth.

Now, let it be assumed that the screw member 42 has been turned so that the inner end thereof does not engage the member 28 in Fig. 1. The member 28 will then be free to turn, and it will turn with the pawl carrier, pawls and rifle bar; and the rifle bar and rifle nut and the associated ratchet and pawl mechanism will cause the hammer piston 4 to rotate intermittently (rotate on its rearward stroke, with the construction shown), and accordingly the motor will operate in the common manner of devices of the automatic rotation, percussive type. This will be understood as soon as it is noted that the normal reaction of the tips of the pawls on the surfaces 52, 53 and 55, 56 is to maintain the rings 28, 28, 28 and 28" in such relative position to the pawl carrier as to permit maximum expansion of the pawls. For example, Figs. 2 and 7 show the normal positions, relative to the pawl carriers, of the rings 28 and 28", when such rings are free to turn.

When, however, (referring to Figs. 1 and 2) the member 42 is screwed in and so acts to pre clude the rotation of the member 28, the down stroke of the piston will cause the rifle bar to rotate counter-clockwise in Fig. 2 and the pawls will be depressed inwardly by the engagement of the rearmost portions of their outer edges with the surfaces 5| within the member 28. When the rearward motion of the piston begins, the pawl carrier will begin to rotate freely in the clockwise direction, instead of acting as a pistonrotating device, for the extremities of the pawls will be kept out of engagement with the ratchet teeth, and so there will be nothing for them to react upon and compel rotation of the piston. Complete cessation of rotation may occur instantly, or within a very small number of strokes, depending on the relation of ratchet ring teeth to pawl location. The rotation ceases at once, if all the pawls fully engage teeth at the same time, and within two or three piston movements if staggered relation is used. Rotation of material degree ceases at once even with the relation last mentioned, though a fraction of a ratchet tooth of advance may occur as the less: fully engaged pawls act on the ratchet tooth tips. However, even if this occurs, as soon as this action is ended complete cessation of all rotary movement occurs. The relatively great length of the surfaces 5|, etc., makes this minute initial turning, if it occurs, immaterial.

When it is desired to resume rotation, the member 42 will simply be screwed back to release the member 28 for rotation with the pawls, and the pawls will simply pick up and carry the member 28 around with them, it being observed that the pawl pairs form couples tending, unless they engage opposite arcuate surfaces struck from the ring center, to rotate the ring 28 counter-clockwise, viewed in Fig. 2, which is the direction of rotation which frees the pawls for engagement with the ratchet teeth. Even if the pawl tips get to such position relative to the ring that their pressure does not directly tend to turn the ring, the differences in friction at different loci between ring, pawls, etc. will quickly cause such relative movement, as soon as the ring is released, as to permit pawl engagement again.

In the construction of Fig. 5, because of the presence of the arcuate portion of the surface 5| (the portion in which points A and B lie), a relatively rapid rotationthat is, a relatively wide range of angular oscillation-of the rifle bar and pawl carrier relative to the ring 28 may take place, and so a fairly steep lead to the rifle bar may be employed. With the construction in Fig. 6, it is desirable to use a rifle bar of smaller lead, and the structure of Fig. '7 may be used with a rifle bar having a very large lead, because of the great length of the surfaces 45. Fig. 8, as above indicated, shows a different form of ring construction, which will accommodate quite a material rifle bar lead.

In each of the forms of my invention illustrated, it will be observed that I have provided a floating member adapted normally to turn the pawl carrier, but effective, when stopped, to render the pawls ineffective. It will be evident that the same concept may be embodied in constructions in which the relative relations of the parts are variously modified.

From the foregoing description, it will be evident that I have provided a very simple and effective construction in which a member free to move with the rifle bar may, upon being retarded in its rotation, diminish or interrupt completely the rate of rotation. It will be evident that the parts are extremely simple and effective in their intended function, and there is little possibility of deterioration by wear, because the parts may be specially heat-treated etc. to improve their durability.

While I have in this application specifically described one form and certain modifications which my invention may assume in practice, it

will be understood that these are shown for purposes of illustration only, and that the invention may be modified further and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawlcarrier elements, said pawl-carrier element carrying pivoted pawls engageable with the teeth of said ratchet element, operative connections between one of said elements and a drill steel to be rotated, means for holding the other element against rotation, and means having internal control surfaces arranged to act upon the ratchetelement-engaging ends of the pawls remote from their pivots to swing said pawls out of engagement with the ratchet teeth for interrupting drill steel rotation at will.

2. In combination, a toothed ratchet member, a cooperating pawl carrier carrying pivoted pawls engageable with the teeth of said ratchet member, said ratchet member and pawl carrier being relatively rotatable, and means acting on the tips of the pawls remote from their pivots to swing the pawls out of engagement with the ratchet teeth thereby to preclude their engagement with the ratchet member, said means effective to prevent such engagement of the pawls with the ratchet teeth when held stationary while relative rotation between said ratchet member and said pawl carrier continues, but normally rotating and ineffective for the purpose stated.

3. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawlcarrier elements, said pawl-carrier element carry ing pivoted pawls engageable with the teeth of said ratchet element, operative connections between one of said elements and a drill steel to be rotated, means for holding the other element against rotation, a rotatable disc arranged with its axis of rotation coincident with the axis of relative rotation between said elements and having internal control surfaces arranged to act upon the ratchet-element-engaging ends of the pawls remote from their pivots for releasing the pawls,

completely from engagement with the ratchet teeth when said disc is held stationary, and means engageable with said disc for holding the latter stationary to effect pawl release from the ratchet teeth.

4. In combination, a toothed ratchet member, a cooperating pawl carrier, said pawl carrier carrying pivoted pawls engageable with the teeth of said ratchet member, said ratchet member and said pawl carrier being relatively rotatable, a control disc rotatable about an axis coincident with the axis of relative rotation of said ratchet mem-' ber and pawl carrier and having internal cam surfaces acting on the tips of the pawls remote from their pivots to preclude engagement of the pawls with the ratchet member, said disc effective to prevent such engagement when held stationary, but normally rotatable and ineffective for the purpose stated, and means engageable with said disc for holding the latter stationary to effect pawl release from the ratchet teeth.

5. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawlcarrier elements, said pawl-carrier element carrying pivoted pawls having associated means by which they are yieldingly pressed into engage ment with the teeth of said ratchet element, said pawls engaging the ratchet teeth to prevent relative rotative movement between said elements in one direction and yieldingly slipping over the ratchet teeth to permit free relative rotation of said ratchet and pawl-carrier elements in the opposite direction, and means operable at will during operation of the rotation mechanism to effect complete release of the'pawls from the ratchet teeth comprising an annular disc rotatable about an axis coincident with the axis of relative rotation between said ratchet and pawlcarrier elements and having relatively inclined internal control surfaces operative, when said disc is held stationary, to engage the pawls to press the pawls out of engagement with the ratchet teeth against the action of the yielding pressing means, said disc movable automatically, when released for free rotation, by the yielding pressing action of the pawls on the inclined internal surfaces thereof, into a position to permit engagement of the pawls with the ratchet teeth.

6. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawlcarrier elements, said pawl-carrier element carrying pivoted pawls having associated means by which they are yieldingly pressed into engagement with the teeth of said ratchet element, said pawls engaging the ratchet teeth to prevent relative rotative movement between said elements in one direction and yieldingly slipping over the ratchet teeth to permit free relative rotation of said ratchet and pawl-carrier elements in the opposite direction, and means operable at will during operation of the rotation mechanism to eifect complete release of the pawls from the ratchet teeth comprising an annular disc rotatable about an axis coincident with the axis. of relative rotationbetween said ratchet and pawl-carrier elements and having relatively inclined internal control surfaces operative, when said disc is held stationary, to engage the outer tip ends of the pawls to press the pawls out of engagement with the ratchet teeth against the action of the yielding pressing means, said disc movable automatically, when released for free rotation, by the yielding pressing action of the pawls on the inclined internal surfaces thereof, into a position to permit engagement of the pawls with the ratchet teeth.

7. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawl-carrier elements, said pawl-carrier element carrying pivoted pawls having associated means by which they are yieldingly pressed into engagement with the teeth of said ratchet element, said pawls engaging the ratchet teeth to prevent relative rotative movement between said elements in one direction and yieldingly slipping over the ratchet teeth to permit free relative rotation of said ratchet and pawl-carrier elements in the opposite direction, and means operable at will during operation of the rotation mechanism to effect complete release of the pawls from the ratchet teeth comprising an annular disc rotatable about an axis coincident with the axis of relative rotation between said ratchet and pawl-carrier elements and having relatively inclined internal control surfaces operative, when said disc is held stationary, to engage the pawls to press the pawls out of engagement with the ratchet teeth against the action of the yielding pressing means, said disc movable automatically, when released for free rotation, by the yielding pressing action of the pawls on the inclined internal surfaces thereof, into a position to permit engagement of the pawls with the ratchet teeth, said disc havingnotches at the junctures of said relatively inclined internal control surfaces for receiving the tip ends of the pawls when the latter are released for engagement with the ratchet teeth and said disc is released for free rotation.

8. In a rock drill, drill steel rotation mechanism including relatively rotatable ratchet and pawlcarrier elements, said pawl-carrier element carrying pivoted pawls having associated means by which they are yieldingly pressed into engagement with the teeth of said ratchet element, said pawls engaging the ratchet teeth to prevent relative rotative movement between said elements in one direction and yieldingly slipping over the ratchet teeth to permit free relative rotation of said ratchet and pawl-carrier elements in the opposite direction, and means operable at will during operation of the rotation mechanism to effect complete release of the pawls from the ratchet teeth comprising an annular disc rotatable about an axis coincident with the axis of relative rotation between said ratchet and pawl-carrier elements and having relatively inclined internal control surfaces operative, when said disc is held stationary, to engage the pawls to press the pawls out of engagement with the ratchet teeth against the action of the yielding pressing means, said disc movable automatically, when released for free rotation, by the yielding pressing action of the pawls on the inclined internal surfaces thereof, into a position to permit engagement of the pawls with the ratchet teeth, said disc having a square opening providing said relatively inclined internal control surfaces and the corners of the square opening at the junctures of the inclined surfaces receiving the tip ends of the pawls when the latter are released for engagement with the ratchet teeth and said disc is released for free rotation.

JOHN L. REILLY. 

